Process of making acetyl-cellulose plastics.



UNITED srarns rampant ora ion WILLIAM G. LINDSAY, OF CALDVTELL, NEWJERSEY, ASSIG NOR TO THE GELLULOID COMPANY, OF NEW YORK, N. Y.', ACORPORATIQN OF JERSEY.

PROCESS 0E MAKING ACEIYL-QELLULOSE PLASTICS No Drawing.

2"0 all whom it may concern:

Be it known that I, l/VILLIAM Ur. LINDSAY, a citizen of the UnitedStates, residing in Caldwell, county'of Essex, State of New Jersey, haveinvented certain new and useful Improvements in Processes of MakingAcetyl-Cellulose Plastics, of which the following is a specification.

' The various'compositions to which the present inventionrelates areemployed in colors and other inert substances, and sometlmes as filmswhich are used for photographic and other purposes.

Although the final. or useful form of the different compounds of acetylcellulose is that of a solid material, the different processes ofconversion into this final solid form involve, as is well understood,the'employment of solutions or mixtures of varying consistency as toplasticity, stiffness, or fluidity, depending generally upon theproportion and kind of solvent used in the amount of the originalbaseacetyl cellulose.

It has been known for many years that camphor and ethyl alcohol inadmixture form a solvent for nitrocellulose in the cold or at roomtemperature, and also that camphor can be mixed with the nitrocelluloseand that the subsequent addition of ethyl alcohol causes solution orconversion ofthe nitrocellulose. It is also well known that campho'r isa combustible substance and that when mixed even with acetyl celluloseand a liquid solvent, the resulting compound is more or lesscombustible, and it was the object ofmy. experiments to find substanceswhich in a suitable combination would effect solution or conversion ofthe acetyl cellulose into a plastic mass which, .upon the applica: tionof heat and pressure can be molded or otherwise worxed in a manneranalogous to the nitrocellulose-camphor' compounds.

In the course of my experiments I have found that acetyl celluloseplastic compounds of the kind desired can be produced by the use oftriphenylphosphate or tricresylphosphate or. a mixture of the two, in

con unction with either methyl or ethyl alcohol; but, as there is anobservable difference between the action of ethyl and methyl alcohol inconjunction with the phosphates, I

Specification of Letters Patent. Patented Feb, 1915. Application filedNovember 27, 1911. Serial No. 662,746,

prefer the methyl alcohol. I also prefer the phate is "more soluble inmethyl alcohol thanin ethyl alcohol. Nevertheless, I have succeeded inproducing useful compounds by the employment of tricresylphosphate andalso triphenylphosphatein con unction with both ethyl alcohol and methylalcohol. Of the-two phosphates, I prefer triphen'ylphosphate for thereason that it seems to exert a more powerful solvent action on acetylcellulose when used in conjunction with the alcohols na'm'ed than doestricresylphosphate.

In this specification and the claims appended hereto, I refer only tothat variety of acetyl cellulose which, is soluble in acetone in thecold. I 7

As an example of carrying out my invention, I take 100 parts of acetylcellulose (soluble in acetone). I add from 10 to '30 parts oftrip'henylphosphate and thoroughly mix the two by grinding, stirring,etc. then add the ethyl alcohol or methyl alcohol, or a mixture of thetwo. ing with 30' to 45 parts of methyl or ethyl alcohol, the massis-allowed to stand from 12'to 24 hours or longer in a covered vessel inorder to secure good penetration.- The After careful mixmass .is thensubjected to heat applied by mold may be of such a. form that the shapefinally desired may be given to the object by this oneoperation. Thesheets or other objects produced by this process are then subcuttinginto sheets in the usual way, or the j'ected to drying or seasoning, asis common with nitro cellulose compounds.

When using the tricresylphosphate the process is similar to that abovedescribed and ethyl-alcohol can be used as stated instead of methylalcohol with both the phosphates, but the solvent thus produced with theacetyl cellulose than when methyl alcoethyl alcohol exerts a more feebleaction on "hol is used; c

It will be understood by the skilled operator that the ingredients ofthe new solvent I mixtures described can be added toI the acetylcellulose in any desired order. It will I also be understood btheoperatfor that vari- J .ous combinations 0 the solvents described canbe used if desired: thus a mixture of triphenylphosphate andtricresylphosphate may be used with either methyl alcohol or ethylalcohol or a mixture of the two alcohols. Again, either one or both ofthe alcohols named may be used singly or in admixture with either ofthe.hosphates'named.

Itshould be stated al vent mixtures can be used in conjunction withother known'solvents that are not incompatible therewith, and withdiluents and coloring matters and other inert substances,

as is common to the nitrocellulose art.

The exact proportions of ingredients named are not essential to thespirit of my invention for they may be changed to some so that my newsoldegree without preventing solvent action under the application ofheat, although 1 prefer the proportions s ecified.

Having thus descri edmy invention, what 1. The process of making acetylcellulose plastic masses which comprises incorporating anacetone-soluble acetyl cellulose with a triarylphosphate having not morethan seven carbon atoms in the aryl group'in the 3 triphenylphosphate inthe presence :or a small proportion ofmethyl alcohol and heat- I ing,substantially as set forth.

Witnesses:

J; HINDON HYDE, MABEL DEN o WILLIAM G. LINDSAY;

